ES3012849T3 - Control plane signaling for integrated access and backhaul nodes - Google Patents

Abstract

Various communication systems can benefit from improved network signaling. For example, certain implementations may benefit from improved connectivity between relay nodes and network entities. One method may include receiving, at a user equipment of an integrated access and backhaul node, downlink information from a donor node. This downlink information may include F1 application protocol information. The method may also include forwarding the downlink information, including the F1 application protocol information, from the user equipment of the integrated access and backhaul node to a portion of the radio access network of the integrated access and backhaul node. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Control plane signaling for integrated access and return nodes

Cross-reference to related applications

This application claims priority to U.S. Provisional Patent Application No. 62/619,479, filed January 19, 2018.

Background

Field

Various communication systems can benefit from enhanced network signaling. For example, certain embodiments may benefit from improved connectivity between relay nodes and network entities. Description of Related Art

The Third Generation Partnership Project (3GPP) for New Radio (NR) or Fifth Generation (5G) technology includes features that enable minimal manual effort when deploying a network using NR or 5G technology. For example, one feature provided is automated self-configuration. When using higher frequency bands, NR or 5G technology also enables easy coverage extension with minimal or no network planning or replanning requirements in a rapid and cost-effective manner. To facilitate this, a wireless backhaul network is used to connect relay nodes, also called integrated access and backhaul (IAB) nodes, to each other and to base stations with a fixed connection.

As described above, a relay node (RN) or IAB node is included as part of a communication system using NR or 5G technology. One or more RN or IAB nodes are connected to each other. The RN or IAB node also has a wireless backhaul connection, instead of a wired connection, that connects the RN or IAB node to a 5G or NR donor Node B (DgNB) or another IAB node. The DgNB is a base station with a fixed connection to the network backhaul. A serving DgNB controls the use of radio resources in the communication system and considers both access and backhaul links as part of the radio resource allocation.

ERICSSON: 3GPP draft “Architecture for integrated access and backhaul” refers to integrated access and backhaul to support NR cells that self-backhaul using the NR radio interface to other NR nodes, which are connected to a traditional transport network.

The 3GPP TS 38-470, v1.0.0 (2017-2) technical specification “F1 general aspects and principles” defines the F1 interface. The F1 interface provides a means to interconnect a gNB-CU and a gNB-DU of a gNB within an NG-RAN, or to interconnect a gNB-CU and a gNB-DU of an en-gNB within an E-UTRAN.

HUAWEI ET AL.: 3GPP draft “Consideration on IAB scenarios and use cases” refers to integrated access and return for NRR and considerations from the perspective of deployment scenarios.

ERICSSON: 3GPP draft “Deployment scenarios and use cases for integrated access control” analyzes the deployment scenarios and topology of IAB use cases.

Summary

An embodiment relates to a method, which includes receiving, at a user equipment part, integrated access and return node downlink information from a donor node, the downlink information comprising at least F1 application protocol information. The method also includes the downlink information comprising at least the F1 application protocol information from the user equipment part of the integrated access and return node to a radio access network part of the integrated access and return node. The downlink information is received at the user equipment part of the integrated access and return node as a radio resource control message or signal. In an exemplary embodiment, a signaling radio bearer may be passed through the return link and the downlink information at the user equipment part of the integrated access and return node may be received through the signaling radio bearer.

Another example relates to an apparatus, which includes receiving means for receiving, at a user equipment part of an integrated access and return node, downlink information from a donor node, the downlink information comprising F1 application protocol information. The apparatus also includes forwarding means for forwarding the downlink information comprising at least the F1 application protocol information from the user equipment part of the integrated access and return node to a radio access network part of the integrated access and return node. The downlink information is received at the user equipment part of the integrated access and return node as a radio resource control message or signal.

In an exemplary embodiment, a signaling radio carrier may be passed over the return link and downlink information at the user equipment portion of the integrated access and return node may be received over the signaling radio carrier.

Another example relates to a method, which includes creating, at a donor node, downlink information for an integrated access and return node, wherein the downlink information comprises at least F1 application protocol information. The method also includes transmitting the downlink information comprising at least the F1 application protocol information from the donor node to a user equipment portion of the integrated access and return node. The downlink information is transmitted from the donor node to the user equipment portion of the integrated access and return node as a radio resource control message or signal.

In an exemplary embodiment, a signaling radio carrier may be passed over the return link and downlink information to the user equipment portion of the integrated access and return node may be received over the signaling radio carrier.

Another example relates to an apparatus including means for creating, at a donor node, downlink information for an integrated access and return node, wherein the downlink information comprises at least F1 application protocol information. The apparatus may also include transmission means for transmitting the downlink information comprising at least the F1 application protocol information from the donor node to a user equipment portion of the integrated access and return node. The downlink information is transmitted from the donor node to the user equipment portion of the integrated access and return node as a radio resource control message or signal.

In an exemplary embodiment, a signaling radio bearer may be passed over the return link, and downlink information may be received by the user equipment portion of the integrated access and return node via the signaling radio bearer. In another exemplary embodiment, the signaling radio bearer may be identified by an identifier, and the identifier may be a logical channel identifier.

Another embodiment relates to a computer-readable medium comprising program instructions stored thereon for performing: receiving, at a user equipment portion, integrated access and return node downlink information from a donor node, the downlink information comprising at least F1 application protocol information; forwarding the downlink information comprising at least the F1 application protocol information from the user equipment portion of the integrated access and return node to a radio access network portion of the integrated access and return node. The downlink information is received at the user equipment portion of the integrated access and return node as a radio resource control message or signal.

Another embodiment relates to a computer-readable medium comprising program instructions stored thereon for performing: creating, at a donor node, downlink information for an integrated access and return node, wherein the downlink information comprises at least F1 application protocol information; and transmitting the downlink information comprising at least the F1 application protocol information from the donor node to a user equipment portion of the integrated access and return node. The downlink information is transmitted from the donor node to the user equipment portion of the integrated access and return node as a radio resource control message or signal.

Brief description of the drawings

For a proper understanding of the invention, reference should be made to the accompanying drawings, wherein:

Figure 1 illustrates an example of a diagram according to certain embodiments.

Figure 2 illustrates an example of a diagram according to certain embodiments.

Figure 3 illustrates an example of a diagram according to certain embodiments.

Figure 3a illustrates an example of a diagram according to certain embodiments.

Figure 4 illustrates an example of a diagram according to certain embodiments.

Figure 5 illustrates an example of a diagram according to certain embodiments.

Figure 5a illustrates an example of a flowchart according to certain embodiments.

Figure 6 illustrates an example of a flowchart according to certain embodiments.

Figure 7 illustrates an example of a flowchart according to certain embodiments.

Figure 8 illustrates an example of a system according to certain embodiments.

Detailed description

In 5G or NR technology, the IAB node may have a user equipment (UE) portion, also known as a UE function or mobile termination (MT) function, that connects to the DgNB or another IAB node, in an embodiment including multi-hop relaying. The IAB node may also include a radio access network (RAN) portion, which serves the UEs or the access UE, as well as secondary IAB nodes connected to the IAB node, also known as next-hop IAB nodes. The RAN portion may consist of a full gNB or a distributed unit (gNB-DU) portion of a gNB. The UE portion, in some embodiments, may be controlled via radio resource control (RRC) signaling. In other words, the UE part of the IAB node can use RRC similar to any normal UE, which means that the donor gNB can configure the UE part of the IAB node by sending RRC reconfiguration messages to the IAB node.

Certain embodiments may help support self-backhaul, where the same bearer can be used for a backhaul connection as well as for access links. In other words, certain embodiments help support in-band backhaul operation. Figures 1 and 2 relate to the transport of control signaling to the RAN portion of the IAB node. In particular, embodiments may allow for the extension of RRC information transfer to carry F1 Application Protocol (F1AP) messages from the DgNB Central Unit (CU) to the RAN/DU portion of the IAB node. In addition to, or in yet another embodiment, a specific type of Signaling Radio Bearer (SRB), referred to as SRBx, may be used to help carry F1 Application Protocol messages from the DgNB CU to the RAN/DU portion of the IAB node. By using SRBx, the UE and/or IAB node can recognize the transmitted signals based on the logical channel IDs (LCIDs). In other words, in one embodiment, the RRC information transfer can be extended to carry the F1AP, while in another embodiment, SRBx can be used to carry the F1AP.

Stream Control Transmission Protocol (SCTP) or Internet Protocol (IP) may be used to transport or transmit, in some embodiments, an F1 Application Protocol (F1AP) from a CU to a distributed unit (DU). With backhaul, the F1AP may be signaled or transmitted over a user plane function (UPF) to the IAB node using a protocol data unit (PDU) session terminating at the UE portion of the IAB node. In other words, a UPF, which may be located at an IAB node CU outside of the donor node, may transmit the F1AP to a UE portion of the IAB node. However, such backhaul signaling using the UPF does not fit well with Layer 2 (L2) relay-based backhaul, since SCTP is, by definition, used on top of L2 protocols and requires the addition of a specific header identifying the protocol as such. Autofallback can be used as part of the automated self-configuration provided by NR or 5G.

Figure 1 illustrates an example of a diagram according to certain embodiments. In particular, Figure 1 illustrates an example of an F1AP for controlling the RAN portion of the IAB node, which may encapsulate messages within control plane traffic. For example, the messages may be included in a transparent container or SRB in the control plane traffic. Certain embodiments, as shown in Figure 1, may include extending the transfer of RRC information to transmit F1AP messages, also referred to as F1AP information, from the DgNB CU to the RAN portion of the IAB node. SRBs, such as SRBx, may also be used in transmitting the F1AP information from the DgNB CU to an IAB node, allowing the signaling to be recognized based on an identity, such as an LCID or information included within the RRC layer carrying the F1AP information. In other words, the LCID may be associated with the SRB, such as the SRBx, or the d Rb, through which downlink data or information may be received.

Figure 1 illustrates a donor node 110, such as a DgNB, including a central unit portion 120 and a distributed unit portion 130. Figure 1 also illustrates the SRBx that may be established between RRC entities at the DgNB CU and the UE portion of the second IAB node. The same SRBx may be passed through a first hop 140, located between the DgNB 110 and a first IAB node 150, and through a second hop 160, between the first IAB node 150 and the UE portion of the second IAB node 170. The first hop 140 and the second hop 160 may be wireless backhaul links. A message or signaling transmitted over the wireless return link, illustrated as SRBx via the first hop 140 and/or the second hop 160, may be recognized using an identity, such as an LCID or information included in the RRC protocol. SRBx, for example, may have an x equal to 2 or it may have an x equal to 4. The same value of x may apply to both hops shown in Figure 1.

The SRB cardinality may be related to the SRB priority. It may be recognized that each SRB, for example, has a different priority based on the number x. For example, SRB2 may be defined as having a lower priority than SRB1 and may be used for NAS message transfer, for example. On the other hand, SRB4 may be defined as having a higher priority than SRB2, but a lower priority than SRB1, and may be indicated as being used at least for F1AP message transfer or transmission between the DgNB and the IAB node. In certain other embodiments, a higher SRB number x may mean a lower priority.

In certain embodiments, downlink information may be transmitted from the DgNB CU 120 to a RAN portion of the IAB node via SRBx through the first hop 140 and/or SRBx through the second hop 160. In other words, the DgNB CU 120 may be for transmission to both the DgNB DU 130 and the RAN portion of the second IAB node 170, which may also be referred to as the IAB node DU portion. The downlink information may include F1 A<p> information. The downlink information, in some embodiments, may be transmitted using RRC signaling and may be transmitted in the form of RRC information, which is information contained in an RRC message. The signaling radio bearer, such as SRBx, may only be used in some embodiments when carrying F1AP information. Using the signaling radio bearer, such as SRBx, exclusively to transmit F1AP information can allow for greater differentiation or prioritization of F1AP information over other traffic. As shown in Figure 1, the DgNB can use the F1AP, which can be sent via the SRBx, to configure the RAN portion of the second IAB node. Receiving the F1AP information can change the configuration of the RAN portion of the IAB node.

Transmission or transport of F1AP information using the dedicated signaling radio bearer, for example SRB4, over the wireless return links and/or transfer of RRC information, for example, using SRB2, may allow for a reduction in protocol overhead in over-the-air wireless transmissions. For example, in certain embodiments, IP or SCTP headers may not be required. As such, an IP header having a minimum of 20 bytes may not be required and/or an SCTP header having a minimum of 16 bytes may not be required. When the dedicated signaling radio bearer is used over the wireless return link, the overhead of RRC messages transmitted to the RAN portion of the IAB node may also be minimized. Furthermore, the embodiment shown in Figure 1 may not use a user plane function (UPF) to transmit the F1AP information, allowing the same DgNB CU to be used for both the DgNB DU and the RAN portion of the IAB node. Figure 1 further allows for reliable transport of messages by using s Rb . At least one of the SRBs, for example, may use a radio link control (RLC) acknowledgment (AM) mode, which may help provide reliable transmission of the F1AP information transmitted via the SRB.

Figure 2 illustrates an example of a diagram according to certain embodiments. In particular, Figure 2 illustrates a user plane, having a UPF 210, used for UE traffic to and from a UE via an L2-based IAB node. As can be seen in Figure 2, the DgNB 211 may have a CU-DU split. A radio bearer may be provided between the DgNB CU Packet Data Convergence Protocol (PDCP) 212 and a UE PDCP 218. The IAB nodes shown in Figure 2 may include functions similar to those of the DgNB DU 213. In certain embodiments, the IAB node may only host at least one lower L2 protocol layer, such as the RLC layer, a medium access control (MAC) layer, and/or a physical layer (PHY).

HARQ retransmissions, in some embodiments, may be transmitted independently for each hop, such as the first hop 214 and the second hop 216, as well as for the Uu interface between the IAB node and the UE. A DRB may be made across the first hop 214 and/or the second hop 216 and across the Uu interface. The example shown in Figure 2 illustrates only one RLC-L (low or light) at a first IAB node 215 and a second IAB node 217, which may mean that the RLC at the IAB nodes may perform segmentation/resegmentation, when necessary, as well as RLC PDU buffering. RLC retransmissions may be end-to-end between the DgNB DU 213 and the UE 218. In other embodiments, the IAB nodes 215, 217 may host a full RLC, meaning that RLC retransmissions may be performed at each hop. When RLC retransmissions are performed at each hop 214, 216, a DgNB with a CU-DU split, similar to the split shown in Figure 2, may be used.

As shown in Figure 2, there may be a UE tunnel between the UPF 210 and the DgNB CU 212, and an F1 tunnel between the DgNB CU 212 and the DgNB DU 213. L2 MAC aggregation may be performed on the first hop 214 and the second hop 216. The first hop 214 and the second hop 216 may be similar to the first hop 140 and the second hop 160, shown in Figure 1, and may allow for user plane transmission to and from the IAB node. In certain embodiments, a user plane function may be included in the DgNB DU portion 213, the first IAB node 215, and/or the second IAB node 217. A user-specific user tunnel may be provided between the DgNB DU portion 213 and the UE 218.

Figure 3 illustrates an example of a diagram according to certain embodiments. Specifically, Figure 3 illustrates an example of a MAC PDU structure. The MAC PDU structure, in certain embodiments, may be the same as the NR MAC PDU structure specified in TS 38.321, except for the UE IDs added for the MAC service data unit (SDU). Where the UE ID may be added by a separate adaptation layer so that it becomes part of the MAC SDU, the MAC PDU may be the same as the MAC PDU as specified in TS 38.321. 3GPP TS 38.321 is incorporated by reference herein in its entirety.

The MAC PDU 310 may include subheaders including an LCID, a MAC control element (MAC CE), a user equipment identification (ID), and/or a MAC SDU. In addition to RLC and MAC, the return link may include an adaptation layer. The adaptation layer may be a separate layer, in some embodiments, or may be part of the MAC or the RLC. UE traffic from a plurality of UEs served by one or more IAB nodes, such as the first IAB node 150 and the second IAB node 170 in FIG. 1 and the IAB node 215 and the IAB node 217 in FIG. 2 , may be aggregated into a single return transport channel using the wireless return links. A return transport channel may mean a transport channel used over the return link.

In certain embodiments, the aggregation of UE traffic by one or more IAB nodes may be referred to as MAC or adaptation layer aggregation. In certain embodiments, the adaptation layer, or alternatively the MAC or RLC layer, may add a UE ID to each MAC PDU or MAC SDU. The UE ID may be used for routing in the backhaul tree under a DgNB. The backhaul tree may include one or more IAB nodes connected to each other.

Figure 3a illustrates an example of a diagram according to certain embodiments. In particular, Figure 3a illustrates a combination of the diagrams shown in Figures 1 and 2, in which the F1AP information may be transmitted or forwarded from the UE part of the second IAB node 170/217 to the RAN part of the second IAB node 170/217. The upper part of Figure 3a illustrates the control plane of the second IAB node and the lower part illustrates the user plane from an access UE point of view. The communication system shown in Figure 3a illustrates the DgNBs 110/211, the first hops 140/214, the first IAB nodes 150/215, the second hops 160/216, the second IAB nodes 170/217, the UPF 210, and the UE 218. The RAN portion of the second IAB node 170/217, which may be located in the user plane, may receive downlink information, such as F1AP information, from the UE portion of the second IAB node 170, which may be located in the control plane. The IAB node 2170 and the IAB node 2217 are the same IAB node; 170 represents control plane operation, and 217 represents user plane operation. The same applies to other network elements in the figure, such as the DgNB and IAB node 1.

Figure 4 illustrates an example of a diagram according to certain embodiments. Specifically, Figure 4 illustrates a UE control plane for L2 forwarding using IAB nodes. As can be seen in Figure 4, a UE non-access stratum (NAS) service is provided in the communications system. The communications system includes an access and mobility function (AMF) 410, a DgNB 411 including a CU portion 412 and a DU portion 413, a first hop 414, a first IAB node 415, a second hop 416, a second IAB node 417, and a UE 418. The embodiment shown in FIG. 4 may be similar to the embodiment shown in FIG. 2 except that FIG. 2 relates to a PDU service in a user plane for UE traffic, while FIG. 4 relates to a NAS service in a control plane for UE traffic.

The network-side RRC may be on a DgNB CU 412, and one or more user-specific user tunnels or SRBs may be provided between the DgNB CU 412 and the UE 418. Data traffic between the DgNB 411 and the UE 418 may be carried using an IAB transport channel, which may include L2 MAC layer aggregation or L2 adaptation layer aggregation. In certain embodiments, NAS signaling may be between the AMF 410 and the UE 418, and may be carried using RRC signaling, e.g., an RRC information handover. As can be seen in FIG. 4 , F1AP information may be carried from the DgNB CU 412 to the DgNB DU 413.

Figure 5 illustrates an example of a diagram according to certain embodiments. In particular, Figure 5 illustrates a control plane for a UE portion of the IAB node. As shown in Figure 5, the NAS service of the IAB node may be transmitted in a communications network including AMF 510, DgNB 511 including a CU portion 512 and a DU portion 513, a first hop 514, a first IAB node 515, a second hop 516, and a second IAB node 517. A new radio application protocol (NGAP) over SCTP may be used to connect the AMF 510 and the DgNB CU 512, an F1 control plane may be used to connect the DgNB CU 512 and the DgNB DU 513, and an L2 MAC aggregation may be used to connect the DgNB DU portion 513 and the first IAB node 515, as well as the first IAB node 515 and the second IAB node 517.

IAB nodes 515 and 517, as shown in Figure 5, may have a UE portion that receives and/or transmits downlink or uplink information over a return link. IAB nodes 515 and 517 may also have a RAN portion, also referred to as an IAB node DU portion, that may receive and/or transmit uplink or downlink information in an access direction. The RAN portion of the IAB node may communicate with the UE itself or with a UE portion of the next-hop IAB node. The UE portion of the IAB node may function similarly to a UE; however, in addition to UE functions, the UE portion of the IAB node may also support any enhancements specified for the return link. The enhancements specified for the return link, for example, may be located at the MAC layer and/or the adaptation layer.

In certain embodiments, control of the UE portion of the IAB node, such as PHY, MAC, RLC, or adaptation layer reconfiguration, may be performed using RRC signaling. The UE portion of the IAB node, for example, may terminate the SRB carrying RRC and NAS signaling. The RRC may be located at the DgNB CU, while the NAS may be located at the AMF. The SRB terminated at a UE portion of the IAB node may be transported across the return links along with, or independently of, normal UE traffic. The aggregation shown in Figure 5 may, in some embodiments, be an aggregation on the same transport channel of the UE traffic and the SRB. To help facilitate routing and multiplexing, the UE portion of the IAB node may have an identification, which may be a UE ID, similar to that of other 3GPP access UEs. The UE ID may be included in the downlink information transmitted from the DgNB to assist the IAB node in identifying an access UE or the UE portion of the IAB node, or in the downlink information forwarded from the UE portion of the IAB node. In other embodiments, the RAN portion of the IAB node may identify the downlink link used to update the configuration of the RAN portion.

The DgNB CU 512 may control the DgNB DU 513 using an F1AP when the DgNB 511 includes a CU-DU split. Thus, in certain embodiments, the DgNB CU 512 may be used to transmit F1AP information to the DgNB DU 513 and the RAN portion of the IAB node. According to the above embodiments, the F1AP information may be transmitted from the DgNB CU 512 to the IAB nodes 515, 517 via one or more return links or hops 514, 516. The F1AP may be transported in a CU-DU split via SCTP and/or IP. When SCTP and/or IP are used for transmissions between the DgNB CU and the IAB nodes, the IP packets may be routed via an internal UPF located at, or co-located with, the DgNB CU. The internal UPF located in the DgNB CU may be used to manage IP routing to IAB nodes and/or the UE. Certain embodiments may utilize a PDU session and/or a Data Radio Bearer (DRB) that may terminate at the IAB node.

In certain embodiments that include a multi-hop backhaul link or one or more individual backhaul links, as shown in Figures 1-5, a RAN protocol and/or an SRB may be used to wirelessly transmit the F1AP information. In other words, a RAN protocol and/or an SRB may be used to transmit the F1AP information over a wireless backhaul link. In the embodiments shown in Figures 1-5, the SRB content may not be tunneled from the CU. Additionally, an SRB may be used instead of a DRB to have a fixed lossless F1AP interface, similar to F1AP over SCTP, between the DgNB CU and the DgNB DU. For example, user plane traffic between the DgNB CU and the DgNB DU may use the GPRS tunneling protocol, the User Data Tunnel (GTP-U).

In some embodiments, an RRC information transfer may be used. The downlink information may be transmitted via the UE portion of the IAB node to the RAN or DU portion of the IAB node. The downlink information may carry or include F1AP information. The UE portion receiving the downlink information may be in an RRC-connected mode. In some embodiments, the uplink information transfer procedures from the IAB node may also support F1AP signaling. Such an embodiment, for example, may be similar to NAS signaling transfer, where the recipient may deduce the intended destination of the message from the message structure. Both RRC procedures, as well as ASN.1, may be enhanced to support the transmission of F1AP information to the IAB node.

As shown in Figure 1, an SRBx may be used for F1AP transmission. An SRB type, e.g., SRB4, may be specified for F1AP information transmission between the DgNB CU and the RAN portion or DU portion of the IAB node. Since SRBs may use fixed LCIDs, information transmitted from the DgNB CU may be identified when the SRBx is used for F1AP transmission. Therefore, the F1AP information or message, in some embodiments, may be transmitted directly from the F1AP layer to the PDCP layer of the SRB4, and the receiver may route the message to the F1AP layer.

Downlink information, such as the F1AP, may be transmitted from a DgNB CU to a RAN portion of the IAB node, also referred to as a gNB DU of the IAB node, via a UE portion of the IAB node in an RRC connected mode. In other words, the dedicated F1 application protocol information may be used to transfer F1AP information specific to the RAN portion/DU of the IAB node between the network and the IAB node. In certain embodiments, the UE and RAN portions of the IAB node may both be in an RRC connected mode, while in certain other embodiments, the UE and RAN portions of the IAB node may be in different modes. For example, the UE portion of the IAB node may be in a connected mode, while the RAN portion of the IAB node may be in an idle mode. The RAN, in certain embodiments, may initiate transmission of downlink information when there is a need to transfer dedicated F1AP information. The RAN may initiate the downlink information transfer, for example, by transmitting a downlink information transfer message from the DgNB to the IAB node. Upon receiving the downlink information, the IAB node or the UE portion of the IAB node may identify the F1AP and forward the received information to upper F1AP layers, for example, to the entity managing the F1AP.

In some embodiments, an IAB control message may be used for transmitting downlink information. The downlink information may include F1AP information. The downlink information may be transmitted over a wireless backhaul network, for example, via SRB4. In certain embodiments, the downlink information may also be transmitted on a downlink control channel, and the RLC serving access point may be in acknowledgment mode. In an acknowledgment mode, the RLC entity may be configured to transmit or receive PDUs over either the downlink or uplink control channel.

Figure 5a illustrates an example of a flowchart according to certain embodiments. In step 520, the donor node central unit, e.g., the DgNB CU, may transmit or forward F1 application information to the RAN part of the IAB node. In some embodiments, the F1 application information may be transmitted through an SRB, such as an SRBx. In step 530, the UE part of the IAB node may receive, e.g., through the SRBx, a message including the downlink F1 application protocol information transmitted from the donor node central unit in step 520. In step 540, the RAN part of the IAB node may receive the F1 application protocol information from the donor node central unit through the UE part of the IAB node. In other words, the UE part of the IAB node can forward the F1 application information and the RAN part of the IAB node can receive the F1 application information forwarded from the UE part of the IAB node.

Figure 6 illustrates an example of a flowchart according to certain embodiments. In particular, Figure 6 illustrates a method or process performed by a UE portion of the IAB node. In step 610, the UE portion of the IAB node may receive downlink information from a donor node, such as a DgNB. The downlink information may include F1 application protocol information. In one example, the donor node may include a donor node central unit for creating the downlink information. In some cases, the donor node central unit may include an internal UPF. The downlink information, for example, may be aggregated with other data on a return link located between the DgNB CU and the UE portion of the IAB node, or between the DgNB CU and the RAN portion of the IAB node. In certain embodiments, an SRB may be passed over the return link. The return link, in certain embodiments, may be used when the IAB node is in an RLC AM. The return link may include at least one RLC layer, a MAC layer, or an adaptation layer. Downlink information received at the UE portion of the IAB node may be received via the SRB. In some embodiments, the downlink information may be received at the UE portion of the IAB node as an RRC message or signal.

The SRB may include an identifier, such as an LCID. The SRB may terminate at the UE portion of the IAB node. In step 620, the UE portion of the IAB node may identify, based on an identifier within the RRC message or the LCID used for the SRB, that the received downlink information should be forwarded to the RAN portion of the IAB node. In step 630, the UE portion of the IAB node may forward the downlink information, which may include the F1 application protocol information, to the RAN portion of the IAB node.

The downlink information forwarded from the UE part of the IAB node to the RAN part of the IAB node may update a configuration of the RAN part of the IAB node. In other words, the RAN part of the IAB node may update the configuration of the RAN part of the IAB node based on the identified configuration received from the central unit of the donor node via the UE part of the IAB node. The RAN part of the IAB node may identify, based on the downlink information or the F1 application information, the updated configuration of the RAN part of the IAB node. In some embodiments, a signal of at least one of a NAS service or a PDU service may be transmitted through the IAB node.

Figure 7 illustrates an example of a flowchart according to certain embodiments. In particular, Figure 7 illustrates a method or process performed by a donor node central unit, for example, a DgNB. In step 710, the donor node may create or compose downlink information for an IAB node. In certain embodiments, where the donor node may be divided into CU-DUs, the donor node central unit may create or compose downlink information for an IAB node. The donor node central unit, in some embodiments, may include an internal user plane function. The downlink information may include F1 application protocol information. The downlink information created in the donor node central unit may be configured for a RAN portion of the IAB node. In some embodiments, the downlink information may be transmitted from the donor node central unit to the UE portion of the IAB node to reconfigure or configure the UE portion of the IAB node. The downlink information created in the donor node central unit for the RAN portion of the IAB node may be RRC protocol information comprising F1 application protocol information. The downlink information created in the donor node central unit for the RAN portion of the IAB node may be configured to update a configuration of the RAN portion of the IAB node.

In step 720, the method may include transmitting the downlink information, including the F1 application protocol information, from the donor node central unit to a UE portion of the IAB node via a return link. The downlink information may be aggregated with other data on the return link. The return link may be used when the integrated access and return node is in a radio link control acknowledgment mode. The return link may include at least one of an RLC layer, a MAC layer, or an adaptation layer. In certain embodiments, an SRB may be transmitted via the return link, and downlink information transmitted to the UE portion of the IAB node may be transmitted via the SRB. The SRB may include an identifier, and the identifier may be an LCID. In some embodiments, the SRB may terminate at the UE portion of the IAB node. In one example, the F1AP information may be transferred by extending the transfer of RRC information to the transport F1AP. In this embodiment, the F1AP information may be encapsulated within an RRC message that may be sent to the UE portion of the IAB node using an existing SRB, e.g., SRB2. In another embodiment, another SRB, e.g., SRB4, may be specified to carry F1AP information. In the latter embodiment, the F1AP information may not be encapsulated in an RRC message, but rather the F1AP message itself is sent via the other SRB. Typically, SRBs transfer RRC messages; however, in the latter embodiment, the RRC may not be involved in the transfer of the F1AP information.

As described above, in certain embodiments, the donor node central unit, e.g., the DgNB CU, may compose or create F1 application protocol information for the RAN portion of the IAB. Furthermore, the donor node central unit may compose or create RRC protocol information including the F1 application protocol information for the UE portion of the IAB node. The donor node central unit may then transmit the F1 application protocol information to the RAN portion of the IAB node via an SRB, such as an SRBx. The F1 application protocol information may be transmitted from the donor node central unit to the RAN portion of the IAB node via the UE portion of the IAB node.

Figure 8 illustrates a system according to certain embodiments. It should be understood that each block in Figures 1-7 may be implemented by various means or combinations thereof, such as hardware, software, firmware, one or more processors and/or circuitry. In one embodiment, a system may include multiple devices, such as, for example, a network entity 820 or a UE 810. The system may include more than one UE 810 and more than one network entity 820, although, for illustrative purposes, only one network entity is shown. The network entity may be a network node, an access node, a base station, an evolved Node B (eNB), a 5G or NR Node B (gNB), a donor gNB, a host, a server, or any of the other access or network nodes discussed herein.

In certain embodiments, an IAB node 830 may include a UE portion that is similar to the UE 810 for communication with the donor node or the RAN portion of a primary IAB node, in a multi-hop embodiment, and a RAN portion that may be similar to a network entity 820 for communication with access UEs or a next-hop IAB node UE portion. In certain embodiments, therefore, a single IAB node may include at least two processors 811, 821, at least two transceivers 813, 823, at least two memories 812, 822, and at least two antennas 814, 824. In other embodiments, the processors, transceivers, memories, and/or antennas may be shared between the UE portion and the RAN portion of the IAB node.

Each of these devices may include at least one processor or control unit or module, indicated respectively as 811 and 821. At least one memory may be provided in each device, indicated as 812 and 822, respectively. The memory may include computer program instructions or computer code contained therein. One or more transceivers 813 and 823 may be provided, and each device may also include an antenna, illustrated respectively as 814 and 824. Although only one antenna is shown, many antennas and multiple antenna elements may be provided to each of the devices. Higher category UEs generally include multiple antenna panels. Other configurations of these devices may be provided, for example. For example, a network entity 820 and the UE 810 may be additionally configured for wired communication in addition to wireless communication, and in such case, the antennas 814 and 824 may illustrate any form of communication hardware, but are not limited to simply one antenna.

Each of the transceivers 813 and 823 may independently be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that may be configured for both transmission and reception. In other embodiments, the network entity may have at least one independent transmitter or receiver. The transmitter and/or receiver (regarding the radio parts) may also be implemented as a remote radio input unit that is not located on the device itself, but, for example, on a mast. Operations and functionalities may be performed on different entities, such as nodes, hosts, or servers, in a flexible manner. In other words, the division of labor may vary depending on the case. One possible use is to have a network node provide local content. One or more functionalities may also be implemented as virtual software applications that can run on a server.

A user device or user equipment may be a mobile station (MS) such as a mobile phone or smartphone or a media device, a computer, such as a tablet computer, provided with wireless communication capability, a personal data digital assistant (PDA) provided with wireless communication capability, a portable media player, a digital camera, a pocket video camera, a navigation unit provided with wireless communication capability, or any combination thereof. In other embodiments, the UE may be a machine type communication (MTC) device or an Internet of Things device, which may not require human interaction, such as a sensor, a counter, or an actuator.

In some embodiments, an apparatus, such as user equipment 810 or network entity 820, may include means for performing or carrying out the embodiments described above in connection with Figures 1-7. According to certain embodiments, the apparatus may include at least one memory including computer program code and at least one processor. The at least one memory including computer program code may be configured to, with the at least one processor, cause the apparatus to at least perform any of the processes described herein. The apparatus, for example, may be user equipment 810 or network entity 820.

The processors 811 and 821 may be implemented by any computing or data processing device, such as a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field-programmable gate array (FPGA), a digitally enhanced circuit, or a comparable device or a combination thereof. The processors may be implemented as a single controller or as a plurality of controllers or processors.

In the case of firmware or software, the implementation may include modules or a unit of at least one auxiliary integrated assembly (e.g., procedures, functions, etc.). The memories 812 and 822 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit such as the processor or may be independent of it. Furthermore, the computer program instructions stored in the memory, and which may be processed by the processors, may be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal, but may also be external or a combination thereof, such as when additional memory capacity is obtained from a service provider. The memory may be fixed or removable.

The memory and computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as the network entity 820 or the UE 810 to perform any of the processes described above (see, e.g., FIGS. 1-7 ). Thus, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions or one or more computer programs (such as an added or updated software routine, applet, or macro) that, when executed in hardware, can perform a method such as one of the methods described herein. In other embodiments, a computer program product may encode instructions for performing any of the processes described above, or a computer program product may be incorporated into a non-transitory computer-readable medium and encode instructions that, when executed in hardware, perform any of the processes described above. Computer programs may be coded using a programming language, which may be a high-level programming language, such as Objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as machine language or assembly language. Alternatively, certain embodiments of the invention may be implemented entirely in hardware.

In certain embodiments, an apparatus may include circuitry that is configured to perform any of the processes or functions illustrated in Figures 1-6. The circuitry, in one example, may be hardware-only circuit implementations, such as analog and/or digital circuitry. In another example, the circuitry may be a combination of hardware and software circuitry, such as a combination of analog and/or digital hardware circuit(s) with software or firmware and/or any portion of a hardware processor(s) with software (including digital signal processor(s), software, and at least one memory that work together to cause an apparatus to perform various processes or functions. In yet another example, the circuitry may be hardware circuit(s) and/or processor(s), such as microprocessor(s) or a portion of microprocessor(s), including software, such as firmware, for operation. Software in the circuitry may not be present when it is not necessary for the hardware to function.

Specific examples of circuits may include content encoding circuits, content decoding circuits, processing circuits, image generation circuits, data analysis circuits, or discrete circuits. The term "circuit" may also include, for example, a baseband integrated circuit or a processor integrated circuit for a mobile device, a network entity, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

8 illustrates a system including a network entity 820 and a UE 810, certain embodiments may be applicable to other configurations, and to configurations involving additional elements, as illustrated and discussed herein. For example, multiple user equipment devices and multiple network entities may be present, or other nodes that provide similar functionality, such as nodes that combine the functionality of a user equipment and a network entity, such as a relay node. The UE 810 may likewise be provided with a variety of configurations for distinct communication of the communication network entity 820. For example, the UE 810 may be configured for device-to-device, machine-to-machine, and/or vehicle-to-vehicle transmissions.

The above embodiments may provide significant improvements to the operation of a network and/or the operation of user equipment and network entities included in the network. In particular, the above embodiments allow 5G or NR signaling to be efficiently extended using regular ASN.1 extension mechanisms, such as using a non-critical extension via an “empty stream”, e.g., an ASN.1 stream, the content of which is left open at definition time and is only defined later. In other embodiments, an ASN.1 extension mechanism may be an extension append group, e.g., an ASN.1 extension mechanism where an “ellipsis” marker is defined within the ASN.1 code, marking a location where new fields may be created later after the ellipsis marker using a predefined syntax, or an open OCTET STRING, e.g., a defined OCTET STRING of ASN.1 fields, but without content, with the content being defined at a later time. The embodiment may also help reduce protocol overhead in wireless transmissions by utilizing SRBx and/or RRC handover information. The DgNB CU may also be used for both the DgNB DU and the RAN portion of the IAB node, which helps reduce the resources required for F1AP transmissions.

The features, structures, or characteristics of exemplary embodiments described throughout this specification may be combined in any suitable manner into one or more embodiments. For example, the use of the phrases “certain embodiments,” “some embodiments,” “other embodiments,” or other similar language throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, the appearance of the phrases “in certain embodiments,” “in some embodiments,” “in other embodiments,” or other similar language throughout this specification does not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner into one or more embodiments.

One skilled in the art will readily understand that the invention, as discussed above, may be practiced with steps in a different order, and/or with hardware elements in configurations different from those described. Therefore, although the invention has been described based on these preferred embodiments, it will be apparent to those skilled in the art that certain modifications, variations, and alternative constructions are within the scope of the invention as defined by the appended claims.

Partial glossary

AMF Access and Mobility Function

BH Return

CU Central Unit

DRB Data Radio Carrier

DU Distributed Unit

F1AP F1 Application Protocol

F1-C F1 control plane

F1-U F1 User Plane

GTP-U GPRS User Data Tunneling Protocol IAB Tunneling Protocol Integrated Access and Return

MAC Media Access Control

NAS Non-Access Stratum

PCDP Packet Data Convergence Protocol (PDU) Protocol Data Unit

RAN Radio Access Network

RLC Radio Link Control

RN Relay Node

RRC Radio Resource Control

SCTP Stream Control Transmission Protocol

SRB Signal Radio Carrier

UE User Equipment

UPF User Plane Function

Claims (11)

1. A method, comprising: receiving (610), in a user equipment part of an integrated access and return node downlink, information from a donor node, the downlink information comprising at least F1 application protocol information; forwarding (630) the downlink information comprising at least the F1 application protocol information from the user equipment part of the integrated access and backhaul node to a radio access network part of the integrated access and backhaul node; and characterized in that the downlink information is received at the user equipment part of the integrated access and backhaul node as a radio resource control message or signal. 2. The method according to claim 1, wherein a signaling radio carrier is passed through a return link, and wherein downlink information received at the user equipment part of the integrated access and return node is received through the signaling radio carrier. 3. A method, comprising: creating (710), at a donor node, downlink information for an integrated access and return node, wherein the downlink information comprises at least F1 application protocol information; and transmitting (720) downlink information comprising at least the F1 application protocol information from the donor node to a user equipment part of the integrated access and return node; and characterized in that the downlink information is transmitted from the donor node to the user equipment part of the integrated access and return node as a radio resource control message or signal. 4. The method according to claim 3, wherein a signaling radio carrier is passed through a return link, and wherein downlink information transmitted to the user equipment part of the integrated access and return node is transmitted through the signaling radio carrier. 5. The method according to any one of claims 2 or 4, where the signaling radio carrier is identified by an identifier and the identifier is a logical channel identifier. 6. An apparatus, comprising: means for receiving, at a user equipment portion (810) of an integrated access and backhaul node (830), downlink information from a donor node, the downlink information comprising at least F1 application protocol information; means for forwarding the downlink information comprising at least the F1 application protocol information from the user equipment portion (810) of the integrated access and backhaul node (830) to a radio access network portion (820) of the integrated access and backhaul node (830); and characterized in that the downlink information is received at the user equipment part (810) of the integrated access and return node (830) as a radio resource control message or signal. 7. The apparatus according to claim 6, wherein a signaling radio carrier is passed through a return link, and wherein downlink information received at the user equipment portion (810) of the integrated access and return node (830) is received via the signaling radio carrier. 8. An apparatus, comprising: means for creating, at a donor node, downlink information for an integrated access and return node (830), wherein the downlink information comprises at least F1 application protocol information; means for transmitting the downlink information comprising at least the F1 application protocol information from the donor node to a user equipment portion (810) of the integrated access and return node (830); and characterized in that the downlink information is received at the user equipment part (810) of the integrated access and return node (830) as a radio resource control message or signal. 9. The apparatus according to claim 8, wherein a signaling radio carrier is passed through a return link, and wherein downlink information transmitted to the user equipment portion (810) of the integrated access and return node (830) is transmitted through the signaling radio carrier. 10. The apparatus according to any one of claims 7 or 9, where the signaling radio carrier is identified by an identifier and the identifier is a logical channel identifier. 11. A computer-readable medium comprising program instructions stored thereon for performing the method according to any one of claims 1-5.